Annexation (Latin ad, to, and nexus, joining) is the legal incorporation of some territory into another geo-political entity (either adjacent or non-contiguous). Usually, it is implied that the territory and population being annexed is the smaller, more peripheral or weaker of the two merging entities. It can also imply a certain measure of coersion, Expansionism or Unilateralism on the part of the stronger of the merging entities. Because of this, more positive words like Political union or Reunification are sometimes preferred.
Annexation may be the consequence of a voluntary cession from one state to another through purchase or other treaty, or of conversion from a protectorate or sphere of influence, or occupation through military conquest. A City might annex unincorporated areas or a Country might annex other disputed territories. The assumption of a protectorate over another state, or of a sphere of influence, is not strictly annexation, the latter implying the complete displacement in the annexed territory of the government or state by which it was previously ruled.
In International relations the term annexation is usually applied when the emphasis is placed on the fact that territorial possession is achieved by force and unilaterally rather than through treaties or negotiations. The cession of Alsace-Lorraine to Germany by France, although brought about by the war of 1870, was for the purposes of international law a voluntary cession. Under the treaty of December 17, 1885, between the French republic and the queen of Madagascar, a French protectorate was established over this island. In 1896 this protectorate was converted by France into an annexation, and Madagascar then became "French territory." The formal annexation of Bosnia-Herzegovina by Austria (October 5, 1908) was an unauthorized conversion of an "occupation" authorized by the Treaty of Berlin (1878), which had, however, for years operated as a de facto annexation. A case of conquest was that effected by the South African War (Second Boer War) of 1899-1902, in which the Transvaal Republic and the Orange Free State were extinguished, first de facto by occupation of the whole of their territory, and then de jure by terms of surrender entered into by the Boer generals acting as a government.
By annexation, as between civilized peoples, the annexing state takes over the whole succession with the rights and obligations attaching to the ceded territory, subject only to any modifying conditions contained in the treaty of cession. These, however, are binding only as between the parties to them. In the case of the annexation of the territories of the Transvaal republic and Orange Free State, a rather complicated situation arose out of the facts, on the one hand, that the ceding states closed their own existence and left no recourse to third parties against the previous ruling authority, and, on the other, that, having no means owing to the de facto British occupation, of raising money by taxation, the dispossessed governments raised money by selling certain securities, more especially a large holding of shares in the South African Railway Company, to neutral purchasers. The British government repudiated these sales as having been made by a government which the British government had already displaced. The question of at what point, in a war of conquest, the state succession becomes operative is one of great delicacy. As early as January 6, 1900, the high commissioner at Cape Town issued a proclamation giving notice that the British government would "not recognize as valid or effectual" any conveyance, transfer or transmission of any property made by the government of the Transvaal republic or Orange Free State subsequently to October 10, 1899, the date of the commencement of the war. A proclamation forbidding transactions with a state which might still be capable of maintaining its independence could obviously bind only those subject to the authority of the state issuing it. Like paper blockades and fictitious occupations of territory, such premature proclamations are viewed by international jurists as not being jure gentium. The proclamation was succeeded, on March 9, 1900, by another of the high commissioner at Cape Town, reiterating the notice, but confining it to "lands, railways, mines or mining rights." And on September 1, 1900 Lord Roberts proclaimed at Pretoria the annexation of the territories of the Transvaal republic to the British dominions. That the war continued for nearly two years after this proclamation shows how fictitious the claim of annexation was. The difficulty which arose out of the transfer of the South African Railway shares held by the Transvaal government was satisfactorily terminated by the purchase by the British government of the total capital of the company from the different groups of shareholders (see on this case, Sir Thomas Barclay, Law Quarterly Review, July 1905; and Professor Westlake, in the same Review, October 1905).
In a judgment of the judicial committee of the privy council in 1899 (Cook v. Sprigg, A.C. 572), Lord Chancellor Halsbury made an important distinction as regards the obligations of state succession. The case in question was a claim of title against the crown, represented by the government of Cape Colony. It was made by persons holding a concession of certain rights in eastern Pondoland from a native chief. Before the grantees had taken up their grant by acts of possession, Pondoland was annexed to Cape Colony. The colonial government refused to recognize the grant on different grounds, the chief of them being that the concession conferred no legal rights before the annexation and therefore could confer none afterwards, a sufficiently good ground in itself. The judicial committee, however, rested its decision chiefly on the allegation that the acquisition of the territory was an act of state and that "no municipal court had authority to enforce such an obligation" as the duty of the new government to respect existing titles. "It is no answer," said Lord Halsbury, "to say that by the ordinary principles of international law private property is respected by the sovereign which accepts the cession and assumes the duties and legal obligations of the former sovereign with respect to such private property within the ceded territory. All that can be meant by such a proposition is that according to the well-understood rules of international law a change of sovereignty by cession ought not to affect private property, but no municipal tribunal has authority to enforce such an obligation. And if there is either an express or a well-understood bargain between the ceding potentate and the government to which the cession is made that private property shall be respected, that is only a bargain which can be enforced by sovereign against sovereign in the ordinary course of diplomatic pressure." In an editorial note on this case the Law Quarterly Review of January 1900 (p. 1), dissenting from the view of the judicial committee that "no municipal tribunal has authority to enforce such an obligation," the writer observes that "we can read this only as meant to lay down that, on the annexation of territory even by peaceable cession, there is a total abeyance of justice until the will of the annexing power is expressly made known; and that, although the will of that power is commonly to respect existing private rights, there is no rule or presumption to that effect of which any court must or indeed can take notice." So construed the doctrine is not only contrary to international law, but according to so authoritative an exponent of the common law as Sir F. Pollock, there is no warrant for it in English common law.
An interesting point of United States constitutional law arose out of the cession of the Philippines to the United States, through the fact that the federal constitution does not lend itself to the exercise by the federal congress of unlimited powers, such as are vested in the British parliament. The sole authority for the powers of the federal congress is a written constitution with defined powers. Anything done in excess of those powers is null and void. The Supreme Court of the United States, on the other hand, declared that, by the constitution, a government is ordained and established "for the United States of America" and not for countries outside their limits (Ross's Case, 140 U.S. 453, 464), and that no such power to legislate for annexed territories as that vested in the British crown in council is enjoyed by the president of the United States (Field v. Clark, 143 U.S. 649, 692). Every detail connected with the administration of the territories acquired from Spain under the Treaty of Paris (December 10, 1898) gave rise to minute discussion.
Though initially ambiguous toward a potential annexation of Kuwait by Iraq, US President George H. W. Bush ultimately condemned Hussein's actions, and moved to drive out Iraqi forces. Authorized by the UN Security Council, an American-led coalition of 34 nations fought the Persian Gulf War to reinstate the Kuwaiti Emir. Hussein's invasion (and annexation) was deemed illegal, and Kuwait remains an independent nation today.